Pump



Dec. 3, 1940. T. v. nlLLsTRM PUMP Filed Aug. 1o, 193s 'r sheets-sheet 1.1.1, 'III ,$1

Dec. 3, 1940- T. v. DILLsTRM PUMP Filed Aug. 10, 1938 'r sheets-sheet' 2Dec.;A 3, 1940. T. v. DlLLsTRM PUMP Filed Aug. 10, 1958 '7 Sheets-Sheet3 l I INVENTOR.

Z1/MM @ATTORNEY '7 Sheets-Sheet 4 T. V. DILLSTRM 4PUMP Filed Aug. 10,1938 Dec. 3, 1940.

T. V. DILLSTRM Filed Aug'. 1o, 195e '7 Sheets-Sheet 6 ATTORNEY. i

Dec. 3, 1940- T. v. DILLSTRM PUMP Filed Aug. 1o, 1938 '7 Sheets-Sheet 7DEU VE@ Y ,05E/0o *j pa VERY Pff/00 "2 Patented Dec. 3, 1,940

UNITED STATES PUMP Torbjmvikmr Diustrm, stockholm, sweden,

assignor to Handelsaktiebolaget Vidar, Stockholm, Sweden, a corporationof Sweden ,Application August 10,

1938, Serial No. 224,211

In Sweden September 2S, 1937 17 Claims.

The present invention relates to plunger pumps for supplying liquid andhas particular reference to pumps of this kind for supplying liquid fuelunder pressure for injection into the cylinders of internal combustionengines.

The requirements for fuel injection pumps are particularly severe. Inorder for such pumps to inject fuel in -a manner providing satisfactoryengine operation they must inject fuel under very high pressure, theymust act with extreme accuracy and precision, they must be capable ofadjustment to vary the quantity of fuel delivered per cycle of operationand they must, when supplying fuel to a multiple cylinder engine, beca-v pable of delivering, as nearly as possible, precisely the samequantity of fuel to each outlet for any given setting of pump capacity.

In order to meet these extremely rigid requirements, the mostsatisfactory type of pump' arrangement heretofore developed has beenthat in which a separate cylinder and plunger is provided for eachinjector or other device to which fuel must be supplied and because ofthe extremeaccuracy with which such pumps must be manufactured and thepressures involved, such pumps have proved to be very expensive tomanufacture and also diicult to maintain in proper adjustment over longperiods of service so that appreciable variation is notI developed,through wear or other causes, in the quantities of fuel delivered todifferent outlets leading for example to injectors in differentcylinders o f the same engine.

It is the general object of the present invention to improve upon priorforms of construction of plunger'l pumps and to provide novel plungerpump structure which will enable liquids such as fuel oil to be suppliedto a plurality of points of consumption with great accuracy of controlboth as to the quantity delivered and the relation of the quantitiesdelivered by the pump to different outlets, while at the same timeoaccomplishing the desired results with pump structure very much moresimple and inexpensive than struc- 4tures heretofore representing thebest availab for accomplishing the desired purpose.

To this end the invention contemplates the F provision of improvedplunger pump structure so constructed that liquid is delivered to aplurality of outlets from a common pump chamber through the action of asingle plunger. 1

'Ihe manner in which the above general object, and other and more speclcobjects of the invention to be hereinafter pointed out, are attained,will best be understood from a consideration of the ensuing .portion ofthis specification, taken in conjunction with the accompanying drawings,in which is described various forms of constructional examples of pumpstructure for carrying the invention into effect.

In the drawings, Fig. 1 is a transverse section 5 of a pump embodyingthe invention, taken in part along the line l-I of Fig. 2 and in partalong line I-I of Fig. 3;

Fig. 2 is a fragmentary section taken line 2--2 of Fig. 1;

Fig. 3 is a section taken on the line 3 3 of Fig. 1; y

Fig. 4 is a section taken on the line 4-4 of Fig. 1;

Fig. 5 is a section taken on the line 5-5 of 15 Fig. 4

Fig. 6 is an enlarged view of pari-l of the pump plunger and barrelshown in Fig. 1, certain passages being turned into the plane of thedrawing for clarity of illustration;

Fig. 7 is a developed view of the plunger and barrel surface of the pumpshown in Fig. 1 with the plunger adjusted for maximum delivery;

Fig. 8 is a series of diagrams illustrating various phases of operationduring the delivery stroke of the type of pump shown in Fig. 1, only twooutlets being shown in the diagrams, however, for the sake ofsimplicity;

Fig. 9 shows different phases of the delivery stroke of a different formof plunger applicable for use in a pump of the general kind shown in on4the Fig. 10 illustrates a di'erent arrangement of outlet openings in apump of the general kind shown in Fig. 1;

Fig. 11 illustrates in developed form the control portion of the plungersurface shown in Fig. 7, but in partial load position of adjustment;

Fig. 12 is a view similar to Fig. 11 showing a different form of controlsurface on the pump plunger for effecting a diierent mode of timing ofpart load delivery with respect to the timing of the pump actuatingmechanism;

Fig. 13 is a view similar to Fig. 12 showing still another form 4of pumpcontrol surface for effecting'yet another mode of timing of part loaddelivery;

Fig. 14 is -a diagram illustrating a preferred cycle of movement of thepump plunger, particularly'with reference to the delivery stroke;

` Fig. 15 is a view showing a form of cam prole for securing the kind ofplunger operation shown in Fig. 14;

Fig. 16 is a fragmentary section showing a form of overiiow arrangementdlerentufrom tha of Fig. 1;

Fig. 17 is a view similar to Fig. 16 showing still another overowarrangement;

Fig. 18 is a partial section showing a different form of pump plungerand barrel construction for use in a pump of the kind shown in Fig. 1;

Fig. 19 is a central longitudinal section ofthe pump barrel of Fig. 18,taken on the lines I8-I9 of Figs. 18 and 20;

Fig. 20 is a top plan view taken on line 20-20 of Fig. 19;

Fig. 21 is a section taken on line 2I-2I of Fig. 19;

Fig. 22 is a series ofe diagrams mustrating dif-A .erent phases ofdelivery stroke operation of the plunger of the type shown in Fig. 18,only two outlets'again being shown in these diagrams for the sake ofsimplicity;

Fig. 23 is a developed view of part of the barrel andplunger surfaces ofthe pump shown in Fig.18;. f

Fig. 24 is a fragmentary section similar to Fig. 1 showing a pump havingthe same type of plungeras shown in Fig. 18 combined witha differentform oftappet construction; l

Fig. 25 is a diagram similar to Fig. 8k showing another form of cylinderporting arrangement Fig. 26 is a diagram similar tov Fig. 25 showingstill anotherv portinggarrangement providing precompression of fuelbefore delivery;

Fig.l 27A is a dia-gram similar to Fig. 26 showing an arrangementproviding variable degrees of precompression;

Fig. 28 is a diagram similar to Fig. 27 but` showing a diiferentvariation of precompression with respect to load adjustment of the pump;

Fig. 29` isa diagram illustrating a diierent form of plunger portingconstruction;

- Fig. 30 is a diagram illustrating the features of Fig.25'applied toadifferent form of plunger;

f vidi'ng for precompression with a plunger of the general type shown inFig. 30; and

Figs. 35 and 36 are diagrammatic sectional anda developed viewsrespectively showing an arrangement providing for variableprecompression with a plunger of the type shown in Fig. 33.

Referring now more particularly to Figs. lato 5,

the pump illustrated isa single cylindernpump adapted topsupply' liquidfuel to four separate placesV of'consumption such as fuel injectors.

The pump comprises a casing part I0 in the base portion of whichthere'is mounted a cam shaft l2 adapted to be driven from any suitablesource of power and carrying cam I4 which may be integral with or xed tothe shaft. At the top of the casing part IB there is secured ahead partI6, which is advantageously removably'xed to part l0 by a number ofbolts, one of whichl is shown at I8.

The pump cylinder orbarrel 20 is, in the embodiment illustrated,detachably secured to the head I6 by means of a threaded yclampingcollar22 and is prevented from rotating with respect to the pump body by meansof a locating pin 24. The pump plunger 28 is reciprocably mounted in thebore of barrel 20 and head I 6 is bored out in alignment with the boreof the barrel t0 valve. This is of importance as will be explainedprovide a pump chamber 28 with which the suction or supply conduit 30communicates. Between the conduit .30 and the chamber 28 there islocated the non-return suction valve which in the form shown is a springloaded ball valve 5 32. It is to be noted in this connection that the owof liquid to the pump chamberfrom the suction line is through astraightchannel substantially unobstructed except for the suction later.

The pump barrel is provided with a series of longitudinally spaced4relief or overflow ports r1,

ra, r3 and r4. .which as will be noted from Figs.

1 and 5 liein alignment in a plane passing l5 through the axis of thepump barrel. These ports are connected respectively by branch overiiowpassages 34a, 34h, 34e and 34d t0 a common overflow passage 34 formedpartially in the barrel and partially in the head part of the pumpcasing.

The pump barrel is further provided with four outlet or delivery portslocated in a zone above the'overfiow ports and advantageouslydistributed so as to open into the bore of the barrel in different axialplanes passing throughvthe axis of the bore. These delivery ports, likethe relief ports; are distributed in longitudinally spaced relationalong the pump barrel. 'One of these ports d1 is shown in Fig. 1 and theremaining three ports, d2, da, d4, appear in Fig. 5.

The ports d1-d4 are connected respectively by delivery passages 36, 38,40 and 42 to individual delivery conduits 36a, 38a, 48a and 42a. Each ofthe several delivery passages is provided with a spring loaded dischargevalve, the one controlling passage 36 being indicated at 44 in Fig. 1.In the embodiment illustrated the several delivery ports are displacedperipherally with respect to adjacent ports by and the line of reliefports is also displaced peripherally with respect to twoV peripherallyadjacent delivery ports (see Fig. 3). As will hereinafter more fullyappear, the arrangement of the outlet ports peripherally of the barrelmay be varied Without affecting pump operation.

'I'he pump plunger is provided with two longitudinally separatedrecesses 46. and 48, both of which are in constant communication withthe pump chamber 28 by means of a central longitudinal bore 58 in thepump plunger, which at one end opens into the pump chamber and which isplaced in communication with the surfaces of the recesses by one orseveral transverse bores 52 and 54 respectively.

In the embodiment illustrated, the recess 46 encircles the periphery ofthe pump plunger while the recess 48 is provided with a specialconguration to be described later.

Between the plunger and the cam there is provided a tappet 56 mountedfor reciprocation in a suitable bore in the casing part I0 and at itslower end provided with a roller 58 contacting the face of the cam. Thetappet is restrained against turning movement in the casing by means ofa locating pin 60 the inner end of which engages a suitable verticalslot 62 in the tappet. y The upper portion of the tappet is of cup-likeform providing a cylindrical recess into which the lower end of the pumpplunger extends and against the bottom of which recess the enlarged foot26a of the plunger rests. The

y The bore of the tappet is shouldered to provide a seat for a retainingwasher 64 through which the plunger passes and which engages the uppersurface of the foot 26a to prevent axial displacement of the plungerwith respect to the tappet. The retainer 64 is held in place by the pumpplunger spring 66 which is compressed between this retainer and thecollar 22. As will be evident from Fig. 1, spring 66 operates to causethe tappet and the pump plunger to follow the path of travel determinedby the-profile of cam I4.

Adjustment of the quantity of fuel discharged by the pump is effected byturning the pump plunger about its axis and in order to effect thiscontrol, a segment 68 is provided having -teeth engaging the rack 'l0slidably mounted for movement axially of itself in the pump casing. Rack'l0 projects from the pump casing for connection to any suitable controlfor manual or automatic adjustment of the delivery capacity of the pump.Turning movement imparted to segment 68 by movement of rack 'l0 istransmitted to the pump plunger by means of al pin 12 fixed at one endin the plunger and at its other end sliding in a vertical slot 'F4 isthe segment 68. APin 12 passes through an arcuate slot 16 in the wall ofthe tappet, which permits the pin to be turned by rack 'lll while thetappet remains rotationally stationary.

Referring now more particularly to Figs. 6 and 7, in which the pumpcylinder and plunger arrangement shown in Fig. 1 has been shown onenlarged scale and in developed form for clarity, the plunger 26 hasbeen shown in its position of rotational adjustment for full loadoperation.

Recess 46, whichmay conveniently be considered as the delivery recess,also constitutes a port in the plunger, defined by edges 46a and 4Gb,which port is conveniently designated as a plunger delivery port todistinguish it from the delivery ports i1-d4, which are convenientlydesignated as cylinder delivery ports.

Recess' 48, which may conveniently be considered .as the overflowrecess, has upper and lower limitingedges 48a and 48e and between andspaced from these edges there is provided a control portion 48 in theform of an islandlike projection which extends partially around thecircumference of the plunger and the surface of which is in contact withthe wall of the cylinder bore. The control portion 48 provides twoparallel transverse control edges 48h .and 48d which operate, as willhereinafter more fully appear, to control the lbeginning and ending offull load delivery periods, and a third inclined edge 48e which in theembodiment illustrated merges at one end with edge 48h and operates tocontrol the beginning of the delivery periods during part loadoperation. By reference to Fig. 7 it will be seen that the space betweenedge 48a 'on the one hand and edges 48h and 48o on the other handprovides a channel 48f in constant communication with the pump chamber,which channel constitutes an overflow port in the plunger which isconveniently designated as a plunger overflow port to distinguish itfrom the cylinder overow ports' 1'1-1'4. Likewise, .a channel 48g,constituting a second plunger overow port longltudinally spaced from theone formed by channel 48f and also in constant communication with thepump chamber, is formed by the space between edges 48d and 48e.

Referring now more particularly to Fig. 8. which shows the plunger invarious positions on its delivery. stroke and in which for the sake ofconvenience only two relief or overflow ports y .3 r1 and r2, and twodelivery ports d1 .and d2, have been shown, it is assumed that the pumpchamber 28 is filled with liquid drawn thereinto fromI the suctionconduit 30 by the preceding suction stroke of the plunger.

In position 8a, the plunger is assumed to beat the bottom of its strokeand about to ascend on its delivery stroke. In this position, the recess46 is not in communication with any delivery port while the channel 481,forming a part of the recess 48, is in communication with the reliefport r1 so that movement of the plunger on its delivery stroke ispermitted by overflow of liquid from the pump chamber through the bores50 and 54 in the plunger and through the overflow recess 48.

In position 8b, the plunger has moved upwardly until the upper controledge of the delivery recess 46 is just passing the lower edge of thedelivery port di, to place port al1 in communication with the pumpchamber by way of bores 56 and 52 in the plunger and the deliveryrecess. At the time the plunger reaches this position, channel 48j isstill in communication with relief port r1 so that when edge 46a passesthe lower edge ofport di to esta/blish delivery communication, deliverydoes not then take place because of the open overflow connection throughthe relief port.

When the plunger reaches the position .80, the delivery port di has beensubstantially opened and when the plunger reaches this position,delivery commences due to the channel 48f having passed out ofcommunication with the relief port r1. This determines the instant ofcommencement of delivery and with the plunger in the full load positionof rotation shown, which corresponds to the position shown in Fig. 7, itwill be evident that commencement of injection is determined by thecontrol edge 48h.

Continued movement of the plunger from the position shown at 8c to theposition shown at* 8d effects delivery through port d1 which, it will benoted, is in communication with the delivery recess 46 during thisperiod of movement of the plunger. When the plunger reaches the position8d, the overflow channel 48g cornes into communication with the reliefport r1 to terminate the delivery period and again by reference to Fig.7 it will be evident that the end of the delivery period will bedetermined by the control edge 48d. 'I'hus the delivery through the portd1, which may be termed delivery period No. 1, occurs during movementlof the plunger from position 8c to position 8d. Also, it will be notedthat the delivery recess 46 is in communication with the delivery portd1 both immediately before and immediately after the delivery period.Stated in another way, the overow periods immediately preceding .andimmediately following -the delivery period overlap the terminal portionsof the period when the plunger delivery port is in communication withthe cylinder delivery port, the actual delivery period'being shorterthan the period of communication between these two delivery ports.temporarily placed in simultaneous communication with a delivery passageand an overflow passage just before actual delivery commences and justafter it ceases.

In the position 8e, the edge 46h of the delivery recess passes the upperedge of delivery port di, overflow continuing to take place during themovement from position 8d to position 8e by the continued communicationbetween overow Thus the pump chamber is channel 48g and relief port n.Before channel 18g passes out of communication with port r1, channel 48jcomes into communication with port r2, and during continued movement ofthe plungmunication with relief port Ti.

Between positions 8h and 8i,.the delivery port d2 is brought intocommunication with 'the delivery recess d6, but no injection takes placeduring this movement because of the continued communication of overflowchannel 48j with relief lport r2 after the overflow channel 18g haspassed out of communication with relief port 1'1. When position 8i isreached, delivery period No. 2 coinmences, since at this instant theoverflow channel 48f passes out of communication with relief port r2 andchannel 48g is already t,out of communication with relief port T1. l

Delivery continues until orelief channel- 48g comes into communicationwith relief port T2 as shown at position 87', communication betweenchannel 48g and port r2 continuing until the delivery recess 46 passesout of communication with port d2 (position 8k) and to the end of themovement of the pump plunger in the direction of its delivery stroke, asshown in position 8l.

It will be noted that in order to secure the desired continuity ofoverflow between delivery periods the(` overflow through the twochannels 48f and 48g overlaps, resulting at certain periods insimultaneous overflow through both of these channels.

It will be evident from the above that with a larger number of deliveryports and overflowl ports arranged in the manner shown in Figs. 6 and 7,the sequence of delivery periods and intervening overflow periodswilltake place as in the manner just described, the number of deliveryperiods corresponding to the number of longitudinally spaced deliveryports provided in the pump cylinder.

In the embodiment just described the delivery ports are located in azone in the pump barrel nearerto the pump chamber end of the barrel thanis the zone in which are located the relief ports. It is, however,immaterial which group of ports is nearer the pump chamber end of thebarrel and the reverse of the arrangement shown in Figs. 1 to 8 has beenindicated in Fig. 9, in which the relief ports r1 and r2 are located ina zone nearer to the pump clamber while the delivery ports di and dz arelocated in a zone further from the pump chamber. Obviously, if thepositions of the groups of cylinder ports are reversed, the positions ofthe delivery and overow recesses in the pump plunger must also bereversed as indicated in Fig. 9. For purposes of illustration the pumpplunger in Fig. 9 has been shown in two positions, b and c,corresponding tothe positions b and c of Fig. 8 and illustrating theapproach to and commencement of the first delivery period.

It will be apparent that any cylinder delivery port may be at any placeon a given circumference lying in ra plane normal to the axis of thecylinder bore without affecting the timing of delivery through the port.In some instances it may be desirable to provide for simultaneousdelivery to two or more outlets, and as will be appreciatedirom Fig. 10,this may readily be actaneous delivery may be made through a pluralityof delivery ports during each delivery period rather than through asingle port.

Referring again to Fig. 7, and having in mind the sequence of operationsduring the delivery stroke explained in connection with Fig. 8, it willbe evident that for any delivery period, as for example the deliveryperiod through port di, the commencement of the delivery period isdetermined by the control edge B817 closing relief port r1 and the endof the delivery period is determined by the control edge 48d openingthis relief port. With the plunger in the position of rotation shown inFig. 7, the distance between these control edges is maximum .andconsequently with the plunger in this position, these edges determinethe maximum period of delivery. Further, as long as the plunger is inany position of rotation where these parallel edges are controlling, thelength of the delivery period will be constant and the relation of thebeginning and end uof the delivery period will not vary with respect tothe positions of rotation of the cam shaft of the pump. If, however, theplunger is rotated to bring the control edge 48o to a position where itpasses port r1, as shown in Fig. 11, itwill be evident that the deliveryperiod Will be shortened because of edge 48e closing port 1'1 only afterthe plunger has travelled farther on its delivery stroke than theposition corresponding to the closing position determined by edge 48h,While the position of the plunger at which the relief port is'opened byedge 48d remains unaltered. Stated in terms of fuel injection to anengine, this arrangement operates upon adjustment for part load tocommence injection at a later time in the cycle of operation of thepump, and consequently at a later time in the cycle of engine operation,while maintaining the end of the injection period constant with respectto the cycle of pump operation. C

For some types of engines it may be desirable to maintain thecommencement of injection constant with respect to the engine cycleinsofar as adjustment of the pump for variations in load is concerned.In order tc accomplish this, the arrangement of the control edges may beas shown in Fig. 12, in which the edge 48o for part load control isinclined oppositely as compared with Fig. 1l. With this arrangement, thecontrol edge 8b closes port r1 with the pump cam in the same position ofrotation regardless of load adjustment of the plunger. At partloadadjustment, however, as shown in Fig. 12, the inclined edge portionopens the relief port earlier in the delivery stroke .than would be thecase for full load adjustment, in which latter case edge 48d wouldcontrol the opening of the overflow.

In Fig. 13, still another arrangement of part load control edge isillustrated, which operates to retard the time of closing of the reliefport with respect to the pump cycle when part load adjustment iseiected, and to advance the time of opening of the relief port withrespect to the pump-cycle when in this position of adjustment. Thearrangement in Fig. 13 in effect combines the arrangement shown in Figs.11 and 12. From the foregoing it will be evident that in a pump'embodying the present invention, substantially any timing variation ofpart load injection with respect to the operation of the engine to whichfuel is being supplied by the pump may be effected by suitablecontouring of the part load control edge.

When the pump is to be used to supply fuel for injection to an engine,the delivery stroke of lthe plunger is advantageously made in a seriesof steps, each step including a period of acceleration, a period ofconstant velocity, and a period of deceleration, and the several steps,one for each injection, being separated by intervening periods when thepump plunger is motionless or substantially motionless.

A curve illustrative of this type of plunger action is shown in Fig. 14,and in Fig. 15 there is illustrated a cam for effecting this type ofmotion. Referring to Fig. 14, the ordinates of the diagram representpump stroke while the abscissae represent cam rotation in degrees. Asindicated on the figure, the scale ofordinates to abscissae isapproximately three to one and the curve is for a cam of the kindsuitable for a pump having four delivery periods per delivery stroke ofthe plunger. On the curve illustrated, the four delivery periods occuralong the portions A, B, C, and D of the curve while the suction strokeis represented by the dotted line portion E of the curve. 'Ihe deliveryperiods are eifected respectively by the rising portions A, B, C, and Dof the cam, these portions being separated by portions I, II and III ofconstant radius which provide for the intervals of no lplunger movementbetween the several injection periods. While portions I, II. and III aremost advantageously of constant radius, they are not necessarily so.'I'he portion E of the cam proiile provides for the suction stroke.

It will be evident that the prole of the cam I may be varied to give acurve diierent in form from that just described, but the curveillustrated has been found to be advantageous for securing goodinjection characteristics.

As will be observed from Figs. 14 and 15 the portion E of the profile ofa cam suitable for effecting a series of delivery periods for eachdelivery stroke, must be relatively steep, and thus this results in ahigh speed suction stroke as well as a suction stroke of greater lengththan would be required for a plunger effecting but one delivery period.For this reason the arrangement of the pump suction passage of the pumpin line with the. cylinder bore, to provide for flow of liquid into thepump chamber without abrupt change in direction, is highly advantageous.

It has been found desirable, in order to insure good deliverycharacteristics. to provide a certain counterpressure or resistance tothe overflow from the several relief ports. This may be accomplished indierent Ways as is illustrated in Figs. 1, 16, and 17. As shown in Fig.1, a spring loaded valve 18 opening in the direction of overow isprovided to maintain a predetermined pressure load on the liquidoveriiowing through the passage 34.

In the arrangement shownl in Fig. 16, the overflow passage 34 has'inserted therein a choke plug 80, the diameter -of the orifice `ofwhich will of course determine the extent of the counterpressuredeveloped by overiiow. In Fig. 17 the overflow passage is restricted bymeans of an adjustable plug 82, bymeans of which the value of theresistance to overflow may be varied as desired.

In the arrangements shown in Figs. 16 and 17, the overiiow is returneddirectly to the suction line 30 and when such direct return of theoverflow tothe suction line is eiected, the return line isadvantageously provided as shown in theseflgures with an air or vaporcollecting pocket 84 located at a high point in the return line andclosed by a removable member such as plug 86 which may from time to timebe adjusted or removed to vent anyair or incondensible gas that may havecollected in the chamber. Obviously, the spring loaded ball valveconstruction shown in Fig. 1 may be embodied in a direct overow returnpassage of the kind shown in Figs. 16 and 17 or the forms of choke shownin the latter gures may be incorporated in an independent overiiow lineof the kind illustrated in Fig. 1. Also, it

will be evident that any individual relief passage i may be restrictedto provide the desired counterpressure acting on the overflow.

Referring now to Figs. 18 to 21, another form of pump embodying theinvention is shown, which differs from the construction shown in Fig. 1only with respect to that portion of the pump illustrated in Fig. 18.This embodiment differs principally from that shown in Fig. 1 by thefact that the delivery and relief ports are not disposed in groupslocated in two longitudinally separate zones in the pump barrel, but arelocated in the same zone, and diierent portions of one plunger recessprovide both the plunger delivery port and the plunger overiiow ports,avoiding the necessity for two longitudinally separated recesses as inthe plunger shown in Fig. 1. One principal advantage of the pump shownin Fig. 18 is that the length of the pump barrel and plunger can be madesubstantially shorter than in the form shown in Fig. 1.

In the present arrangement, passages 34a, 34h, 34e, and 34d, whichterminate at their inner ends respectively in the relief ports r1 to r4,are bored directly through from the opposite side of the pump barrel 28aand communicate with an annular relief passage 34e which in turncommunicates-with the passage 34. The annular passage 34e is providedbetween the exterior of the pump barrel and the wall of a recess 88formed in the head portion lia of the pump casing, the pump barrel beingheld in position axially by means of a nipple' 22a threaded into therecess in the head, and suitably packed against leakage of overflowliquid by packing 90. The barrel is centered by one or more anges suchas the one indicated 20h and is restrained against turning movement bymeans of locating pins the recesses for which are shown at 24a in Fig.20.

In this embodiment the several cylinder delivery ports are at the sameheight in the pump barrel as the corresponding cylinder relief ports andas will be observed from Fig. 18, the bores 34h and 34e for relief portsr2 and 1'3 are carried through to the opposite side of the bore toprovide the corresponding delivery ports dz and d:

l which in turn communicate with the delivery passages 38 and 40. Portsd2 and da thus lie in the same axial plane as the relief ports. Ports diand d4, as will be seen more clearly from Fig. '19, lie in a plane atright angles to the plane of ports da and da. Ports d1 and d4 and thetransverse passages connecting them with their respective outletpassages I6 and 42 are advantageously formed by continuations 'ofauxiliary bores 92 and 94 winch provide openings through the barreldirectly opposite and in line with these ports. The l auxiliary bores 82and 94 may be closed by plugs in the same manner that the auxiliarybores,`the contlnuations of which form portions of the overow anddelivery passages of Fig. 1, are closed by plugs 96, but as willhereinafter appeanthe bores srsv s essary' to permit thicon'tinuedmovement Iiseff r fected by the continued` registration of passage 92and 94 may be left open without detriment to operation ofthe pump.

As will be more clearly apparent from Figs. 20 and 21, the deliverypassages 36and 42 lie close together' on the same radial line where theyemergev from the top of the barrel and passages 38 and 40 lie closetogether on a second radial line,- at 'right angles to the rst line,where theyy emerge from the top of the barrel.

lIn. order to symmetrically locate the pump outlets and toipro'vide room"for the several discharge valves, thevh'ead lportion of thev pumpcasing is advantageously arranged in the same manner as sliowii' in Fig.3` and the portions of the outlet passages in the head are brought intocommunication with the portionsin the barrel by means of twoA channels4Gb and-'42h which respectively provide communication between theportions of channel'slfand 42 in the headand in the barrel which wouldotherwise be displaced from each other by 90, f

'Turning now toFig. `22, the operation ofthe punipon itsdischargerstroke is illustrated in much'the'f's'ame manner as'theoperation of the p'umpof Fig;v 1 is illustrated in Fig. 8'. Y

"As in Fig. l8 the diagram; for simplicity, shows only two rather thanfour cylinder delivery ports, and corresponding relief ports. 'Therecess in the pump lplunger in the present 'embodiment is shaped toprovide control edges similar in nature and functio'nto thecontrol edgesshown in Fig. 7

and''need not again be described in detail. In this instance, however,the portion of the recess inuline with the cylinder delivery portsiii-d4 providesthe plunger delivery port; Y

`'In position 22a therecess' is in communication'with the delivery po'rtdi and 'is also in com' munication with`therelef port T1 by way of thepassage 48j. Upward movementY of the plunger doesnotoresult incommencement of delivery untilposition 22h is reached, in'which positionpas-` sage 48f passes) out 'of communication with portA r11" Delivery'continuesl after position 22h is passed untilposition 22e is reached,when de-y -livery is terminated by passage 48g coming intoregistration'with port r1. As the plunger advances from position 22ethrough positions 22d, 22e, and 223, passage 48g passes port r1, throughwhich 'overflow occurs and during this period passage 48f comes intocommunication with relief port r2. By the time position 229` is reached,the recess lrhas passed out of communication with delivery port di' andis in communication with delivery port d2, but delivery through thevlatter port does not commence until the plunger has` reached theposition 22h in `which position the channel 481 passes out ofcommunication with relief port r2. Passage 48g has passed out ofcommunication with relief port 1'1 prior to this I time, when theplunger is in position 22g. 'I'he second delivery period occurs duringmovement of tlie plunger. from position 22h to position 221'.Whenthelatter position is reached, channel 48g comes into communicationwith port rz to termi- `nate injection, .ip uring the remainder of theplungerstroke, to position 22j, the overflow nec- Mig, with ,port jrg.as in they form described in connectiontwith Fig. 8, it will be'apparentthat' the` ;action. just described'may be continued foradditional cylinder' ports placed labovel those Shown in Fig. 22.

adjusted rotationally for full load operation. For

In the. uiagram'just describeditne plunger is.

vbeen described in connection with the pump shown in Fig. 1 and thedesired timing of-ipart load delivery may be eiected in the presentembodiment, as in the previously described embodiment, by suitablyshaping the part load control edge 48o in any desired Way.

It will be remembered that in connection with the constructionillustrated in Fig. 19, it was pointed out that the auxiliary bores 92and 94 for vforming the delivery ports d1 and d4 might be leftv openwithout detriment to operation. of the pump. This will be more clearlyapparent from a consideration of Fig. 23 showing the ported portion ofthe pump' barrel developed together with the control recess and edgeportion of the 'pump plunger.

As will be seen from this figure, which has been l shown with theplunger adjusted for part load operation after having covered port r1and the port formed by the bore 92, the control edge 68h covered bore 92before edge 48e covered relief port' r1 to start delivery through portd1. From the yfigure it will further be apparent that bore 92,whichwould if open act as a relief channel, will not be opened onfurther movement of the pump plunger before the relief port r1 isopened, since edge 68d will'pass both of these ports at the same time.Ifthe'plunger is turned to full load position, that is, moved to theleft in Fig. 23 so that the edge 48h is in line With the line of reliefports,` it will be evidentthat this edge will close port 92 as soon orsooner than the relief port n. Stated in another way, the bore 92 will,inv all positions' of adjustment of' the pump plunger, be'covered for aperiod as long or longer than' the period when relief vport r1 iscovered, so thatbore 92" can never have any effect on or in any wayinterfere with the timing of the delivery period throughl port di,regardless of the position of adjustment of the plunger with respect toload. Likewise, port 94 can in no way affect the delivery period throughport d4, which is controlled by the covering and uncovering of therelief port n.

With the passages in the pump barrel disposed as above described, itwill be apparent that all of the transverse passages for both deliveryand overiiow may very easily'and readily be made byA and aids in one ofthe objects of the invention which is to produce a satisfactory pump forthe purpose intended which may be-manufactured at substantially lower costs than pumps heretofore available.

In Fig. 24 there is shown another form of tappet construction which forpurposes ofvillustration has been applied to a pump of the general typeshown in Fig. 18 in which the relief and delivery ports are located inthe same zone along the length of the barrel. It is of course equallyap# plicable tothe type of pump shown in Fig. 1. In this embodiment, thebarrel 29h is clamped to the head portion |61)l of vthe pump c'asing bymeans of a threaded collar 22h. In the present arrangei this meanscomprises 'aV ring member 68a seated in a suitable bore 1n the casingportion lob and having teeth meshing with the load control rack a. Thering 68a is held against longitudinal displacement by a bearing ring 9Twhich is in turn maintained in position by a snap ring 98 seating in asuitable circular recess in the casing. The tappet 56a is extended atits upper end to form only a shallow cup-like recess for the receptionof the plunger head 26a which is held in position by the retainingwasher 64d. The tappet is restrained against turning by any suitablemeans such for example as a locating pin working in a vertical slot inthe tappeti or by a lower skirt embracing the sides of the cam, andturning movement is imparted to the plunger by means of the pin 12afixed at one end in the foot of the plunger and at its other end slidingin slot 14a in ring 68a. Pin 12a passes through an arcuate slot16a inthe tappet in the same manner as in 1 the construction shown in Figs. 1and 2.

The tappet and plunger are in this instance loaded by means of two heavyhelical springs 66 and 66a ccncentrically arranged between the retainingwasher and shouldered portions of the barrel structure. The use of theadditional and comparatively large diametered spring 66a is `madepossible in the present instance because 0f the fact that the turningmeans for the plunger is located above rather than around the tappet sothat the springs do not have to extend downwardly into the tappet andconsequently have available a space of larger diameter than would be thecase with the construction shown in Fig. 1 and with a tappet of equalcross-sectional dimensions. Thus, in the form shown in the presentfigure, a more powerful spring loading can be obtained without having toenlarge this portion of the pump structure.

From the foregoing description it will be evident that in accordancewith the present invention a single barreled pump structure can beprovided which is relatively cheap to manufacture as compared withmultiple plunger pumps and which will at the same time be capable ofsupplying fuel accurately and in an accurately adjusted quantity to aplurality of separate outlets.

`Because of the fact that control of the timing of the beginning andending of each delivery period is effected by a single plungercooperating with definitely positioned ports, the possibility ofvariation between the quantities delivered to any two different outletsis substantially eliminated, re-

gardless of the position o f adjustment of the plunger with respect toload and also regardless of wear on the pump. If the pump cylinder andbarrel wears, the tendency of such wear is to affect all deliveries tothe sameextent, which is not true. of multiple cylinder pumps where wear`v of unequal magnitude frequently occurs as between different pumpplungers and cylinders. Furthermore, since one pump plunger and cylinderassembly serve to eiect a multiplicity of deliveries, the manufacture ofeach pump and cylinder assembly is facilitated because of the fact thatthe exactness of the matching of the dimensions of cylinder bore andplunger diameter, required for the different pump units of a multiplepump, is not required.

In Figures 25 to 36,' inclusive, further different forms of plunger andbarrel construction are illustrated, which provide for regulation of thedelivery of the fuel from the pump chamber to the delivery conduits invarious diierent manners from that which has been described. In order toillustrate these different forms of pump plunger and barrelarrangements, diagrams similar to those of Figs. 8 to 10, 22 and 23 havebeen employed, since the remainder of the pump construction may be thesame as shown in Figs. 1, 18, or 24. For the sake of simplicity, only somuch will be described in detail with reference to the additionalfigures as differs from the structures heretofore described.

The arrangement shown in Fig. 25 differs from the previously describedembodiments in the location and arrangement of the relief or overflowports in the barrel, with respect to the plunger overflow ports.Referring now to the gure it will be observed that the plunger 26 is ofthe form illustrated in Fig. 8 in which a separate plunger deliveryrecess 46 and a plunger overilow recess 48 are provided. In the presentinstance two de- ^livery ports d1, d2 are shown, and three overflowports ri, r2, and :r3 are provided. The plunger has been shown in twopositions c and d corresponding to positions c and d of Fig. 8 andillustrating respectively the commencement and termination of a deliveryperiod.

As will be observed from position 25o, the delivery period through portdi is about to Acommence, since the upper control edge 48h of thecontrol projection 48 is just passing out of communication with theoverflow portfi to terminate overow by way of the plunger overflow port48f. In this positionthe delivery recess 46 has already moved intocommunication with port di. As the plunger moves from the position c tothe position d, delivery is effected in the manner previously describedin connection with Fig. 8 but the deposition d by the control edge 48aof the recess- 48 passing the lower edge of the relief port r2 so Vthatoverflow takes place due to communication between the plunger overowport 48j and the overflow port r2. This takes place before the plungeroveriiow port 48g comes into communication with port r1.

It will be evident that by similar action, delivery through port d2 willbe commenced by plunger port 48j passing beyond overflow port r2 andwill be terminated by port 481 coming into communication with port r3.

As will be seen from the above, this arrangement differs from thearrangement illustrated in Fig. 8 by the fact that commencement andtermination of a delivery period is in the present case determined bythe action of a. single plunger overiiow port in conjunction with twocylinder overflow ports, whereas in the arrangement shown in Fig. 8commencement and termination of a delivery period are determined by theaction of two different plunger overflow ports acting in IconjunctionWiththe same cylinder overflow port. In some cases the presentarrangement has proved useful rather than the arrangement 'illustratedin Fig. 8.

In the arrangement shown in Fig. 26, the location of cylinder deliveryports and cylinder overflow ports with reference to each other and tothe plunger ports is such as to provide a certain degree ofprecompression of the fuel in the pump chamber before delivery iscommenced so that for each delivery period, high pressure delivery fromthe very instant of commencement of the delivery period may be insured.

VReferring now to Fig. 26, the plunger is of the general form shown inFig. 8 but with the inclination of the part load overflow control edge48e the same as in Fig. 12. The arrangement further is similar to thatshown in Fig. 8 in that the commencement and ending of the deliveryperiods is eiTected by plunger ports 48j and 48g cooperating with thesame overiiow port rather than by the arrangement shown in Fig. 25. InFig. 26 positions c and d have also been shown corresponding, in so faras termination and ending of overflow are concerned, to positions c andd of Fig. 8. As will be observed from position 26C, the plunger overflowport 48j has just passed out of communication with the relief port r1 sothat the liquid is at this point trapped in the pumpv chamber 28. In thepresent arrangement it will be noted, however, that the plunger deliveryport 46 is not yet in communication with the delivery port d1 andconsequently compression of the trapped liquid is effected bymovement ofthe plunger from position c to position c. In the latter position theupper edge 46a of the plunger delivery port passes the lower 'edge ofport di to commence the delivery period, and delivery continues throughport d1 until overilow is again established by registry of plunger port48g with overiiow port ri.

In similar'manner, precompression for the delivery period through portdz is eiected by port 481e passing out'of communication with port r2before the plunger delivery port 46 comes into communication with portd2.

In the embodimeutiuustrated in Fig. 26, the amount of precompressionisconstant regard- -less of the rotational position of the plunger forload adjustment. Variation of the degree of precompression withvariations in load adjustment may, however, be readily accomplished asillustrated in Figs. 27 and 28.

In the form shown in Fig. 2'7 the upper and 'lower control edges 46a and46h respectively of the plunger delivery recess 46 are in planes normalto the axis of reciprocation of the plunger 26, as in the formspreviously described, and consequently communication between the plungeroveriiow port and any given delivery port will be established and cutoff in the samestroke posiplunger overflow ports 48j and 48g areinclined.

With these ports thus inclined it will be evident that any givenoveriiow period will be commenced and terminated in diierent strokepositions of the plunger for different positions of rotationaladjustment thereof. In the figure, the plunger is .illustrated with theoverflow port 48j just passing out ofrcommunication with the overflowport r2 to start precompression prior to registration of port 46 withport d2. It will be seen from the iigure that if the plunger is turnedto reduce the quantity delivered, that is, so that the control edge 46cmoves to the left from the position shown in the ligure, the plungerport 48j will pass out of communication with the overow port r2 in alower stroke position of the plunger than the position shown in thedrawing. This evidently will result in a higher degree of precompressionof the fuel before delivery through the port dz can take place since thepump plunger must travel a greater distance during the interim betweenthe cut-off of overiiow and the registration of the delivery ports.

'-I'hus it will be seen that with this arrangement, the degree ofprecompression increases with adjustment for decrease in load anddecreases with adjustment for increase in load.

Variation in the degree of precompression for different load values mayalso be accomplished as shown in Fig. 28 in which figure the overiiowcontrol edges 68a, ib, lld, and 48e are in planes normal to the axis ofreciprocation of the plunger 5 so that the times of beginning and endingof the overflow periods remain constant with respect to the strokeposition of the plunger regardless of the rotational position ofadjustment of the latter. In the present instance control edges 46a, 10and 46h of the delivery port 46 are inclined, and in order to illustratethe diierent ways in which the relation between degree of precompressionwith respect to load may be varied, the edges of the delivery port havein this form been illus- 15 trated as inclinedjn such manner as toproduce increase in the value of precompression upon adjustment toincrease the load, which is the reverse of the variation' obtained withthe form shown in Fig. 27. In Fig. 28 the plunger is again 20 shown withthe overflow through port r2 just being termin-ated to start theprecompression period, the position of adjustment of the plunger beingfor full load. If now the plunger is turned to bring the control edge48e into play, it will be 25 evident that a higher portion of thecontrol edge 46a will be in axial alignment with the delivery port d2and consequently less plunger movement will be required after overowceases in order to bring the delivery port 46 into communication;y 30with the cylinder port d2. This obviously will result in lessprecompression.

It will be evident from the embodiments shown in Figs. 27 and 28 thatincrease in the degree of precompression with either increase in load or35 decrease in load may be ,obtained as desired by proper sloping, ineither case, of the control edges of either the plunger delivery port orthe plunger overflow ports, or both. In the 'forms illustrated in Figs.27 and 28, the shape of the control pro- 40 jection 48' is such as toprovide for constant commencement and variable termination of injectionwith respect to the pump cycle in the manner previously described inconnection with Fig. 12, but this obviously may be varied.

The character ofy` overflow control eiected by means of the island-likecontrol projection 48', described in the previously discussed`embodiments, can also as readily be obtained by means of a recess in thepump plunger as illustrated by 50 the embodiment shown in Fig. 29. Inthis embodiment the plunger is provided with an overow recess 48 and aninclined control edge 48o and a lower control edge 48e". These edgesbetween them provide an overflow channel 48g". 55 'Ihe positions oi' theplunger shown at 'c and d correspond respectively to positions c and dof Fig. 25 and illustrate the commencement and termination of aninjection period. In position c the plunger overow port is just passingout of communication with overflow port r1 to start the delivery periodthroughport di. This delivery period is terminated when position d isreached, in which position port 48g" comes into communication with theoverflow port fr.

In the embodiments illustrated in Figs. 30 to 34, the various featuresillustrated iny Figs. 25 to 29 are shown applied to pumps havingplungers of the type shown in Fig. 18, which have but one recess, thegeneral action-of which pumps has been described in detail inkconnection with Figures 18 and 22.

Fig. 30,i1lustrates the action with this type of plunger when a singleplunger ,overilow port, acting in conjunction with two cylinder overflowvide between them an inclined overflow port' ports, determines thecommencement andending ofa delivery period. Position b of Fig. 30 showsthe plunger inthe position where delivery through port d1 is commencingdue to port 48j passing out of communication with port r1, and positionc illustrates the termination of this delivery period which is caused byport 48j coming into communication with port r2.

Fig. 31 illustrates a variation in which a single plunger overiiow port48f is provided rather than two spaced ports 48j and 48g as in thepreviously described embodiment. In position b the port 48j has justpassed out of communication with overflow port r1 to commence deliverythrough port di, this delivery period being terminated by port 483registering with port r2, as shown in position 'c. By the time port 48fhas closed port r2 by passing out of communication with this port asillustrated by position d, the plunger port is in communication with thedelivery port d2 and the second delivery period commences, continuinguntil the position e is reached when port lsf comes into communicationwith overflow port ra. It will be evident that turning the plunger tobring the inclined control edge 48e into action will vary the durationof the delivery periods in the same general manner previously described.

Fig. 32 shows a construction producing action corresponding to thatproduced by the form shown in Fig. 29. In Fig. 32, position b againshows delivery commencing through port d1 due to port 48j' passing outof communication with port r1, and position c shows the ending of thedelivery period, caused by port 48f coming into communication with portr2. The action taking place in Fig. 32 as compared with that takingplace in Fig. 31 is different in that in Fig. 32 termination of thedelivery period is varied with respect to the pump cycle with differentload adjustments of the plunger whereas in Fig. 31 the commencement ofthe delivery period is varied with respect to the pump cycle as theposition of the pump plunger is adjusted for diiferent loads.

In the embodiment illustrated in Figs. 33 and 34, an arrangement isshown for producing precompression with a plunger having a single recessand functioning similarly to the arrangement illustrated in Fig. 26.-Fig. 33l shows the plunger and barrel in diagrammatic section while Fig.34 shows the surfaces developed into a plane view. In this arrangementthe bottom edge 48e of the plunger recess 48 is in a plane normal to theaxis of reciprocation of the plunger while the upper edge 48a isprovided with an offset portion 48a' into which the control projection48T extends` so that the plunger overflow port 48f isat a differentlevel from that of the delivery port provided by the main portion of therecess 48. As will be evident from Fig. 33, the control port 8f passesout of communication with the overfiow port r1 before the edge 48areaches the delivery port d1. thus'providing for a period ofprecompression before the latter port is uncovered. Evidently the sameaction will take place on the next delivery period when the controlprojection 48' will cover the port r2 before the edge 48a. uncovers thedelivery port d2.

Variation of precompression for diierent load adjustments of the pumpmay also readily be accomplished with this general arrangement asillustrated by the embodiment shown in Figs. 35 and 36. This arrangementis the same as described in connection with Figs. 33 and 34 except thatthe edges 48a. and 48h' are inclined to pro'- passage 48j'. As will beclearly evident from Fig. 6, rotational movement of the plunger willoperate to vary the amount oplunger travel required between the positionwhen an overflow port is covered by the projection 48 and the positionwhen the next cylinder delivery port is opened.

While in Figs. 35 and 36 the slope of the port 481 has been shown suchthat a greater degree of precompression is effected as adjustment ismade for lower load, it will be obvious that the inclination of thisport may be made in the opposite direction to produce the oppositerelationship between the degree of precompression and value of loadadjustment.

In all of the embodiments hereinbefore described, the several overflowports have all been illustrated as being in the same axially extendingplane, and cooperating with a plunger which in any given position ofload adjustment travels axially without any turning movement. Thisarrangement is to be preferred but it will be apparent that the line ofoveriiow ports might be arranged otherwise, for example, spirally and incooperation with a plunger to which a corresponding spiral motion isimparted by means of an inclined guide slot in the plunger adjustingring.

Also, while the preferred form of ports has been described andillustrated, in which the cylinder delivery ports are circular and theplunger delivery ports are elongated, it will be evident that the'samefunction is readily obtainable by utilizing circular plunger deliveryports and elongated cylinder delivery ports.

Several modifications hereinbefore described clearly illustrate the factthat the invention may be carried out in many different specific wayswhich are capable of producing different delivery characteristics. It isto be noted, however, that it is characteristic of all modificationsthat pump overow permits advancement of the pump plunger on its deliverystroke between spaced delivery periods. This permits separate injectionsof fuel to different cylinders of an engine to be made by the pump wherethe number of engine cylinders and the timing of the injection periodsfor the engine are such that time intervals must elapse between thetermination of one injection period and the commencement of injection tothe cylinder next to be supplied with fuel.

lWhile for the purposes of this specication the pump structuresembodying the invention have been described principally in connectionwith use as for example as an oil pump for supplying lubricating systemsand the like.

It will be apparent that many vchanges and modiiications may be made inthe several embodiments hereinbefore described, and that certainfeatures may be employed to the exclusion of others, Without departingfrom the principles of the invention, and the invention is accordinglyto be understood aslimited in its scope only by the scope of theappended claims when they are construed'as broadly as is consistent withthe state of the prior art.

'Thebroad generic subject matter herein disclosed forms the claimedsubject matter ofv my co-pending application Serial No. 275,974, iiledMay 26, 1939, as a continuation-impart of the What is claimed is:

1. A pump including a cylinder having a plurality of delivery ports anda plurality of overflow ports, and a cooperating plunger ported to placedelivery ports and overflow ports alternately and successively incommunication with the pump chamber during the delivery stroke of theplunger.

2. A pump including a cylinder having a plurality of longitudinallyspaced delivery ports and a plurality of longitudinally spaced overflowports, and a cooperating plunger ported to place the pump chamber incommunication successively with diie'rent longitudinally spaced deliveryports at different times during the'delivery stroke, said plunger beingfurther ported to place the pump chamber in communication successivelywith diierent longitudinally spaced overflow ports at different timesduring the same delivery stroke.

3. A pump including a cylinder having a plurality of longitudinallyspaced cylinder delivery ports and a plurality of longitudinally spacedcylinder overow ports, and a plunger having a circumferentiallyextending recess intermediate its ends and-in communication with thepump chamber, said recess providing a plunger delivery port located tocommunicate with diilerent cylinder delivery ports in different plungerpositions on the discharge stroke and further providing twolongitudinally spaced plunger overow ports located to communicate insequence with the same cylinder overow port in diierent plungerpositions on the discharge stroke to determine the duration of theperiod of delivery through a corresponding cylinder delivery port. Y

'4. A pump including a cylinder having a plurality f longitudinallyspaced cylinder delivery ports and a plurality of longitudinally spacedoverflow parts located in the same zone longitudinally of the cylinderbore, and a cooperating plunger ported to provide plunger delivery portmeans located to communicate in different plunger positions on thedelivery stroke with different cylinder delivery ports, said plungerfurther being ported to provide plunger overflow port means located inthe same zone longitudinally of the plunger as the plunger delivery portmeansv but peripherallydisplaced therefrom 'for communication withdifferent cylinder overflow ports in diiferent plunger positions on thedelivery stroke to determine the duration of the different periods ofdelivery through said cylinder delivery ports, said plunger port meansbeing in communication with the pump chamber.

5. A pump including a cylinder having a plurality of longitudinallyspaced cylinder delivery ports located in a flrst zone in the cylinderbore and a plurality of longitudinally spaced cylinder overow portslocated in a second and longitudinally diierent zone in the cylinderbore, and a' cooperating plunger ported to provide plunger delivery portmeans located to communicate in diiierent plunger positions on thedelivery stroke with different cylinder delivery ports, said plungerfurther being ported to provide plunger overflow port meanslongitudinally spaced from the plunger delivery port means and locatedto communicate in different plunger positions on the discharge strokewith diierent cylinder overflow ports to determine the duration of thedifferent periods of delivery through said cylinder delivery ports, saidplunger port means being in communication with the pump chamber.

6. A pump including a cylinder having a plurality of longitudinallyYspaced eylinder delivery ports situated in diierent axial planes and aplurality of cylinder overflow ports longitudinally spaced in line inthe cylinder, and a. cooperating plunger having a plunger delivery portlocated to communicate with different ones-oi said cylinder deliveryports in different positions of the plunger during ,its delivery stroke,said plunger further having longitudinally spaced plunger overflow portslocated to communicate with different ones of said cylinder overflowports in diierent positions of the plunger during its delivery stroke todetermine the duration of the diierent periods of delivery through saidcylinder delivery ports, all of said plunger ports being incommunication with the pump chamber.

. '7. A pump including a cylinder having a plurality of longitudinallyspaced cylinder delivery ports and a plurality of longitudinally spacedcylinder overflow ports, and a cooperating plunger having a plungerdelivery port in communication with the pump chamber and located tocommunicate successively with a plurality of said longitudinally spacedcylinder delivery ports during one delivery stroke of the plunger, andsaid plunger further having a plurality of longitudinally spaced plungeroverflow ports in communication with the pump chamber and located tocommunicate in succession with said cylinder overflow ports to determinethe durations of the different periods of delivery through said cylinderdelivery ports.

8. A plunger pump including a cylinder having a plurality offdeliveryports and a plurality of overow ports, and a Yplunger ported to placedelivery and overflow ports in communication with the pump chamber inalternation to provide alternating delivery and overow periods duringthe delivery stroke of the plunger, certain of the overflow and deliveryports being temporarily in simultaneous communication with the pumpchamber.

9. A plunger pumpl including a cylinder having a plurality oflongitudinally spaced delivery ports communicating with different .pumpoutlets, a plurality of longitudinally spaced overflow ports, and aplunger ported to place the delivery and overow ports in communicationwith the pump chamber in predetermined order during the delivery strokeof the plunger to provide alternating delivery and overflow periodsduring said delivery stroke, said plunger having control edgescooperating with the cylinder overiiow ports during the delivery strokeof the plunger to determine the timing and duration of the overflowlivery stroke of the plunger to provide alternating delivery andoverflow periods during said delivery stroke, said plunger havingcontrol edges cooperating with the cylinder overflow ports during thedeliveryY stroke of the plunger to determine the timing and duration ofthe overflow periods, whereby to determine the timing and duration ofthe delivery periods, at least one of said control edges being inclinedwith respect to the axis of reciprocation of the plunger to vary theduration of said overfiow periods when the plunger is turned to bringdifferent portions of said inclined edge into cooperating relation withthe cylinder overflow ports, and control means for adjusting theposition of rotation of the plunger with respect to the cylinder.

11. A plunger pump including a plurality ofl longitudinally spacedcylinder delivery ports and a plurality of longitudinally spacedcylinder overflow ports located respectively at the same levels in thepump cylinder as the delivery ports, a plunger having acircumferentially encircling recess intermediate its ends, a passageproviding communication between said recess and the pump chamber, and anisland-like control projection extending from said recess to provideplunger overflow ports above and below the projection, said cylinderoverflow ports being arranged in line, and plunger actuating means forreciproeating the plunger in a position of rotation such that saidcontrol projection follows said line of cylinder overflow ports, wherebyto determine delivery periods from the cylinder by determining thetiming of the overflow through said cylinder overflow ports.

12. A plunger pump including a plurality of longitudinally spacedcylinder delivery ports and a line oi longitudinally spaced cylinderoverflow ports, a ported plunger having a circumferentially encirclingrecess intermediate its ends, a passage providing communication betweensaid recess and the pump chamber, an island-like pro y jection ofirregular shape extending from said recess to form plunger overflowports above and below the projection, at least one of said ports beingof different axial extent at peripherally differentplaces on theplunger, means for reciproeating the plunger with said projectionfollowing the line of cylinder overflow ports, and means for turning theplunger peripherally within a range oi' movement in which saidprojection remains in line with said ports to bring different portionsof said plunger overow port of dierent axial extent into communicationwith said cylinder overiiow ports to vary the duration of the overowperiods.

13. A plunger pump having a cylinder and a plurality of overow portsconnected to different flow pump outlets, a line of longitudinallyspaced overports in the cylinder, a plunger ported to cooperate withsaid overflow ports and with said delivery ports to determine a seriesof delivery periods from the cylinder to said outlets during thedelivery stroke of the plunger, a cam for actuating said plunger,` atappet interposed between the cam and the plunger, a control membermounted for turning movement iTi the casing ad- Jacent thelower end ofthe plunger, said member being restrained against axial movement, meansconnecting said plunger and said member to cause them to turn together,there being a sliding oonnection between said member and said plunger topermit reciprocation of the plunger relative to said member, saidsliding connection guiding the plunger'to cause the plunger overflowports to follow the line oi said cylinder overflow ports during thedelivery stroke oLthe plunger.

14. A pump including 92 plunger and a cylinder cooperatively ported todeliver to different pump outlets atA different times during thedelivery stroke of the plunger andi` having a line of longitudinallyspaced overow ports arranged in said cylinder in a single axial planeforcontrollingV axial reciprocation oi' the plunger without turn' ingmovement relative to the axial line of overflow ports in any givenposition of rotation of said turnably mountedmember. 15. In a plungerpump, a cylinder having a plurality of delivery ports opening laterallyinto the bore of the cylinder, each of said ports constituting the inletof a delivery passage formed in. part by a laterally extending bore inthe wall of the cylinder, a plurality of cylinder overflow ports openinglaterally into the bore of the cylinder and constituting-the inlets ofoverflow passages passing through the wall of the cylinder, at leastcertain of said laterally extending bores constituting extensions ofauxiliary bores extending through the wall ofthe cylinder opposite therespective delivery ports, and a, ported plunger operating in saidcylinder, said ports and said bores being so located in the cylinderwith respect to each other and to the plunger ports that said auxiliarybores are covered by the plunger whenever said overflow ports arecovered.

16. A pump including a cylinder having a series of delivery portsaxially spaced from each other in the cylinder bore and a series ofoverflow ports axially spaced from each other in a pepherally diiierentpart of the bore from the delivery ports, there being at least one moreport in said series of overflow ports than in said series of deliveryports, and a plunger reciprocably mounted in said bore having a.delivery port located to register with the series of cylinderdeliveryports in sequence during one discharge stroke and having an overflowport located to register with the series of cylinder overflow ports insequence during the same discharge stroke, the several ports beinglocated to bring the coooperating overflow ports and the cooperatingdelivery ports into communication in alternation during said stroke andwith overflow ports being the ilrst and the last to communicate duringsaid stroke.

17. A pump including .a cylinder having a series of delivery portsaxially spaced from each other in the cylinder bore and a series ofoverow ports axially spaced from each other in a peripherally differentpart of the bore from the delivery ports. there being the same numberof' ports in each series, and a plunger reciprocably mounted in saidbore having a delivery port located to register with said series ofcylinder delivery ports in sequence during one discharge stroke andhaving A two axially spaced overilow ports each located to

